1. Field of the Invention
The present invention generally relates to a fan module for an electronic device, in particular, to a fan module for enhancing thermal efficiency of the electronic device.
2. Description of Related Art
In order to meet requirements of rapid velocity, high performance and light, thin, short and small of current electronic products, each kind of portable electronic devices has become more popular. Most popular portable electronic devices, such as notebook PCs, mobile phones, Personal Digital Assistants (PDAs), pocket PCs and Tablet PCs etc. As for notebook PCs, since it can not provide a large space for receiving a heat dissipation system, one of critical point to be paid attention is how to enhance the thermal efficiency of the notebook PC in such limited space. Generally speaking, the notebook PC is equipped with a fan module for dissipating heat from the heat-generating device in the interior of the notebook PC. When the fan module operates, the air with high temperature in the interior of the notebook PC passes through an air inlet to enter the fan housing of the fan module and escape through an air outlet to dissipate heat out of the notebook PC, thereby cooling down the internal temperature of the notebook PC.
FIG. 1 illustrates a schematic view of a conventional fan module. FIG. 2 illustrates a schematic view of another conventional fan module. Referring to the FIG. 1 and FIG. 2, the fan module 100 is disposed underneath a mother board 10 of an electronic device or on top of a casing 20 of the electronic device, while the dimension of the fan module 100 is restricted by the limited space between the mother board 10 and the casing 20 of the electronic device, incapable of receiving a bigger size of fan module. Thereby, the maximum height of the fan housing 110 only has 8 mm, and the gap G between the fan housing 110 and the casing 20 underneath the fan housing (or the mother board 20 above the fan housing) is very small, only enable an air flow F passing through a small slot. Hence, the air flow F enters the fan housing 110 through the air inlet is effected accordingly. In addition, the fan module 100 is disposed with a vane module 120, a fan motor 130 and a circuit board 140 in the fan housing 110, and as a result, the size of the vanes 122 close to the vane hub 124 must be shorted to keep away from the circuit board 140 and prevent the interference with the circuit board 140 in structure when the vane 122 is rotating. However, since the size of the vanes 122 is reduced, the capacity of the air flow F to the fan module 100 and the capacity (outlet capacity) of the air flow S exited from the fan module 100 are relatively effected so as to be reduced, thereby reducing the thermal efficiency of the fan module 100 for the electronic device.